Chlorella virus NY-2A encodes at least 12 DNA endonuclease/methyltransferase genes.
The 380-kb chlorella virus NY-2A genome is highly methylated; 45% of the cytosines are 5-methylcytosine (5mC) and 37% of the adenines are N6-methyladenine (6mA). Based on the sensitivity/resistance of NY-2A DNA to 80 methylation-sensitive DNA restriction endonucleases, the virus is predicted to encode at least 10 DNA methyltransferases: 7 6mA-specific methyltransferases, M.CviQI (GTmAC), M.CvQII (RmAR), M.CviQIII (TCGmA), M.CviQIV (GmATC), M.CviQV (TGCmA), M.CviQVI (GmANTC), and M.CviQVII (CmATG): and 3 5mC-specific methyltransferases, M.CviQVIII [RGmC(T/C/G)], M.CviQIX (mCC), and M.CviQX (mCGR). Five of the 6mA methyltransferase genes, M.CviQI, M.CviQIII, M.CviQV, M.CviQVI, and M.CviQVII, were cloned and sequenced. In addition, 2 site-specific endonuclease activities, R.CviQI (G/TAC) and NY2A-nickase (R/AG), were detected in cell-free extracts from NY-2A virus-infected chlorella. Therefore, the NY-2A genome contains at least 12 DNA methyltransferase and endonuclease genes which, altogether, compose about 3-4% of the virus genome.
Zhang
Y
Y
Department of Plant Pathology, University of Nebraska, Lincoln 68583-0722, USA.
Nelson
M
M
Nietfeldt
J
J
Xia
Y
Y
Burbank
D
D
Ropp
S
S
Van Etten
J L
JL
D000595:Amino Acid Sequence; D002708:Chlorella / Q000821:virology*; D019175:DNA Methylation; D015254:DNA Modification Methylases / Q000235:genetics* / Q000302:isolation & purification; D003850:Deoxyribonuclease I / Q000235:genetics* / Q000302:isolation & purification; D005814:Genes, Viral / Q000235:genetics; D008969:Molecular Sequence Data; D017862:Phycodnaviridae / Q000201:enzymology / Q000235:genetics*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
D015254:DNA Modification Methylases; D003850:Deoxyribonuclease I